Atherosclerotic disease of the vertebrobasilar system is an important etiology of posterior circulation stroke. As compared with the anterior circulation, large or small vessel occlusive disease is a more prevalent source of stroke than thromboembolism. Symptomatic vertebrobasilar disease (VBD), particularly if it affects intracranial vessels, carries a high stroke risk averaging 10-15% per year despite medical therapy. Advances in technology, especially in the arena of endovascular therapy have created new options for treatment of VBD. However, the selection criteria for appropriate candidates for either surgical or endovascular revascularization has been problematic.